This invention relates to cigarettes, and more particularly to cigarettes having segments or zones, each segment or zone comprising a tobacco having characteristics different from that of the other segments or zones.
A significant problem facing the cigarette industry is the development of new products. One area for cigarette improvement is the general perception of smokers that cigarettes tend to become more "harsh" as the cigarette is consumed. Another area for significant improvement would be the development of a cigarette that delivers full smoking "satisfaction" at "tar" and nicotine levels below those made possible by the current technology. The present invention points the way to the development of products that meet both those needs.
Understanding of the invention will be enhanced by brief consideration of some basic principles. First, a smoker experiences cigarette smoke as a discrete series of puffs, not in terms of the total cigarette characteristics. Further, it is recognized that smoking characteristics, in terms of the "tar" and nicotine contained in the smoke, very from the first puff to the last, with both measures increasing generally linearly with each puff. One explanation for this phenomenon is the deposition of "tar" and nicotine from early puffs on the tobacco toward the rear of the cigarette. The recurring process of deposition and revolatilization produces smoke higher in these constituents as the product is consumed. It also has been generally recognized that the smoker's perception of the "strength" of the cigarette is directly related to the amount of nicotine contained in the cigarette smoke during each puff.
The only solution offered by the prior art is to vary the nicotine content of portions of a cigarette. Disclosures suggest a multi-blend cigarette, having two separate tobacco blends--a high-nicotine blend at the front of the cigarette and a low-nicotine blend toward the rear. This arrangement is said to overcome the increase in nicotine delivery in the last few puffs and provide more uniform delivery during smoking. This approach was first propoed in British Pat. No. 250,063, in 1925. Similar disclosures include those of Thornton, in U.S. Pat. No. 3,759,267; Wahle, in U.S. Pat. No. 4,009,722; Beretz, in French Patent Application No. 79 20341; and in Brazilian Patent Application No. 820879. Other disclosures, discussing the use of tobacco substitutes instead of low-nicotine tobacco toward the rear of the cigarettes include that of Owens, U.S. Pat. No. 3,902,504.
All of these disclosures share two traits. First, modification of smoking characteristics is defined as being possible solely through varying the nicotine level between front and rear segments, with no other factors involved. Second, no commercially viable product has ever been introduced employing the inventions disclosed.
One inventor realized that density could play a role in smoke modification, but he did so incorrectly. In U.S. Pat. No. 4,328,817, Naylor disclosed a cigarette in which tobacco density preferably decreases continually along the rod from front to rear. Naylor rejected any other configuration. These cigarettes are said to reduce total particulate matter delivered by the cigarette, but no modification of per-puff deliveries is suggested. As will be seen, Naylor teaches directly away from the present invention.
Otherwise, the only application of density control to cigarette manufacturing has been the so-called "dense ending" technique, whereby the ends of the tobacco rod are compacted during rod formation in order to reduce the amount of tobacco spilling from those open ends during manufacture or use. Typical of such disclosures is U.S. Pat. No. 3,604,429. Conventional equipment produces a relatively dense area in both ends of the tobacco rod, with a length of up to about 121/2 mm. maximum, or about 25% of the rod length.
The prior art eloquently testifies to the failure of the industry to develop a successful cigarette offering modification of conventional delivery patterns. The present invention meets that long-felt need.